Marijuana messes with attention, motivation, memory, and learning. The teen brain is still growing and drug use can really cause some damage. Regular heavy marijuana use by teens can lead to an IQ drop of up to 8 points - that’s a lot.1

Starting to use when you’re a kid leads to an increased risk of future drug use. Of those who do start young, one in six will go on to be dependent on marijuana.2 Withdrawal symptoms are real and can include: anxiety, feeling restless, having trouble sleeping, not wanting to eat, stomach pain and moodiness.3

Marijuana can be addictive. It affects the brain in the same way as other drugs and the earlier someone starts to use, the more likely they may become addicted.4

Research has shown that bad reactions can include anxiety (with or without panic attacks) and psychotic symptoms.5

Marijuana has also been linked to an increased risk of schizophrenia.6

Drivers who use marijuana within three hours of driving are 2.5 times as likely to cause a car crash as those who are not drunk or high.7

The THC found in marijuana impairs the body’s immune system, making it harder to fight infections. 8

Marijuana smoke and tobacco smoke contain many of the same cancer causing ingredients.8 Regular, heavy smokers of marijuana report chronic cough and symptoms of chronic bronchitis. Most researchers agree that chronic, heavy use of marijuana increases cancer risk.9 Marijuana can cause increased heart rate and can raise it for up to 3 hours after smoking.10

Getting high from marijuana is associated with impaired judgment, leading to risky behaviors like unprotected sex and dangerous driving.11 In 2005, nearly 242,000 people were admitted to emergency rooms with marijuana-related problems.12

Heavy marijuana use by teens is linked to:

Lower grades and exam scores

Less likely to graduate from high school

Less likely to enroll in or graduate from college

Lower satisfaction with life

Earning a lower income

Being unemployed13

Compared to nonusers, heavy marijuana users more often say they have: more relationship problems, lower life satisfaction, poorer physical health, and less academic and career success.14

Sources:

1Meier et al 2012.

2Hall & Degenhardt 2009; Kalant 2004

3Ashton, 2001 A Review of the Literature on the Adverse Consequences of Marijuana Use: Center for the Application of Prevention Technologies- SAMHSA.

4National Institute on Drug Abuse. Drug Facts Marijuana. 2012 and California Society of Addiction Medicine. Impact of Marijuana on Children and Adolescents. 2009

5Hall & Degenhardt, 2009. A Review of the Literature on the Adverse Consequences of Marijuana Use: Center for the Application of Prevention Technologies- SAMHSA.

6Degenhardt & Hall, 2006. A Review of the Literature on the Adverse Consequences of Marijuana Use: Center for the Application of Prevention Technologies- SAMHSA.